math help

What is 25/15 + 8/11?

What is 25/15 + 8/11?

This is how we add

25
15
+
8
11

Step 1

Can you add yet? Nope! The denominators don't match. We need a common denominator. So next we take both denominators and multiply them. Next, take each numerator and multiply it by the denominator of the other term.

So, we multiply 25 by 11, and get 275, then we multiply 15 by 11 and get 165.

25/15 times 11

Now for the second term. You multiply 8 by 15, and get 120, then multiply 15 by 11 and get 165.

8/11 times 15

We now have a new problem, that looks like this:

275
165
+
120
165

Step 2

Since our denominators match, we can add the numerators.

275 + 120 = 395

Answer:

395
165

Step 3

Now, do we need to simplify this fraction?

First, we attempt to divide it by 2...

No good. So next you try the next prime number, which is 3...

No good. So next you try the next prime number, which is 5...

Are both the numerator and the denominator evenly divisible by 5? Yes! So we reduce it:

395
165
÷ 5 =
79
33

So far so good... let's try to divide by that number again.

No good. So next you try the next prime number, which is 7...

No good. So next you try the next prime number, which is 11...

No good. So next you try the next prime number, which is 13...

No good. So next you try the next prime number, which is 17...

No good. So next you try the next prime number, which is 19...

No good. So next you try the next prime number, which is 23...

No good. So next you try the next prime number, which is 29...

No good. So next you try the next prime number, which is 31...

No good. So next you try the next prime number, which is 37...

No good. 37 is larger than 33. So we're done reducing.

And we're done! Here's the final answer to 25/15 + 8/11

25
15
+
8
11
=
79
33
© 2014 Randy Tayler